A rare form of currency only found on the moon's surface. While it is nearly impossible to be obtained, some people require payment via moon money. Moon money is counted in such a way that humans have not yet figured out the rate of exchange between normal currency and moon money, for the system in which it is calculated is near incomprehensible. It is also used in Pokemon.

I'm sorry, we cannot let you in to the pasta dinner. Here we require moon money.....